Modelling and acoustic monitoring of grout propagation in sands
Résumé
Grouting is generally used for ground reinforcement or
for reducing soil permeability. However, choosing
grouting parameters or predicting improvements is at
present rather empirical. A numerical approach may
therefore enable grouting to be more efficient. The
purpose of this paper is to model the evolution, in time
and space, of two major variables: grout concentration
and fluid pressure in grouted soil. After a brief
description of a first tried diffusive model, this study
aims to describe the performance of a software
program, Athos. This program was initially developed
for the oil industry and uses a piston model. Results are
given in one- and three-dimensional approaches. They
underline a rapid evolution of concentration from grout-
saturated zones to non-saturated zones. The evolution of
pressure depending on this degree of saturation is also
highlighted. The second part of the paper compares the
numerical model with a series of experiments carried
out on grouted sand columns and in saturated sand
tanks. In the latter tests, the grout is injected into the
sand using a sleeved grout pipe, and the progress of
grout propagation in the soil is monitored by acoustic
emission (AE). This comparison shows the validity of the
chosen model. The permeation distance detected by AE
is compared with that predicted by simple grout
propagation models.
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